We review the results of our work on the iodine interaction withthioamides, selenoamides, and amides. Complexes with i “spoke” or “extendedspoke” structures, D⋅I2 and D⋅I2⋅I2, respectively, D is the ligand donor ii iodonium salts of{D2−I+In−} n=3, 7 and {D2−I+FeCl4−} formulae and iii disulfides of the categoriesa D-D, b {D-DH+I3−} have been isolated andcharacterized. A compound of formula {D2−I+I3−D⋅I2} containing both types of complexesi and ii was also isolated.The interaction of diiodine with selenium analogs of the antithyroid drug 6-n-propyl-2-thiouracil PTU, of formulae RSeU 6-alkyl-2-Selenouracil results in the formation of complexes with formulae RSeUI2. All these results are correlated with the mechanism ofaction of antithyroid drugs. Finally, we review here our work on the diiodine interactionwith the amides LO.